Guest OS Loses Network Connection

Description

Running VirtualBox 3.1.6 on a Mac OS X Server 10.6.3 Host on an XServe, with CentOS 5.4 Guest. The Guest OS loses its network connection (both host-only and nat) within 5-10 minutes of startup. The network appears up, but I cannot access the Guest from the Host, nor can I get out from the Guest to the internet, lan or host machine. Restarting networking within the Guest does not fix the problem, nor does restarting the Guest OS. Saving the VM state and starting it again seems to be the only means of re-establishing network connectivity. I have also noticed, however, that continuous network access (i.e., pinging the guest) seems to keep it accessible. Strangely, this same VM setup works fine on 10.6.3 non-server on a Mac Pro.

So what I can recommend do not restore the state just let vm to boot in normal way.

Tried this, but still a Guru Meditation error. I've attached the log file for reference.

Hm ..., ok I'll put release library with enabled logs.

I've uploaded release bits, so it shouldn't be any guru for you. Could you please try with these bits? It gives less logs but at least it should produce events trace to the release log file. So you can run your vm in usual way just attach new log from vm.

'host-only networking' means ability to access to host from the guest only.

Yes, my setup is 2 interfaces, 1 - host-only, for access to that vm directly from the OS X Server host (which also acts as a public web proxy for the private vms) or via VPN; and, 2 - nat for external internet access for each vm.

So, the main problem is that this host <-> guest communication fails after 10 minutes or so unless I have a continuous ping occuring. Previously, the external internet access also failed, but this seems to be working properly now.

Have you compared this with 3783 and tried setting the MTU to 1468? I see that you're also reporting problems with NAT, which may mean this is something else again. Not sure about CentOS having MTU problems, either, as I've noticed that not all guests seem to be inhibited by the MTU issue (e.g. OpenBSD and Ubuntu seem to handle it alright, whereas OpenSolaris and Windows not so much).

Does it happen in combination NAT + Host-Only or can be achieved with Host-Only? Could you please dump guest route information on your SL and SL server hosts, might be caused by some guest misconfiguration?

Issue still present in 3.2.8. The problem results with NAT + Host-only and Bridged + Host-only. I'll check with just Host-only when I have a chance. The routes are fine - as I mentioned, everything works well as long as a ping keeps the network alive. Also, I have noted that when I run two guest machines, I only need to ping one to keep the host-only networks alive on both.

Now I've change the adapter type to: Intel PRO/1000 T Server (82543GC) and it takes about 1 hour before the connection is lost.
It looks like its lost because ping times out or ping time is more than 20000.000 ms.

Now I've change the adapter type to: Intel PRO/1000 T Server (82543GC) and it takes about 1 hour before the connection is lost.
It looks like its lost because ping times out or ping time is more than 20000.000 ms.

I'm going to try the next adatpter

I just wanted to let people know that with my setup.
Host: Windows 7 Ultimate (64 bit) running VBOX 3.2.6 r63112
and Guest (Windows XP sp3),
I have been losing guest network connectivity.
I also have two nic cards configured one for Host ONly the other for NAT.

The connectivity sometimes drops when I try and surf a website.
Other itmes when I try and connect up a running jboss to connect to an external database.
I was running continous pings to an external host so I know the continous pings didn't seem to help keep the ntwork connectivity alive.(at least in my case).

I cannot confirm Martin's observations. Both machines here have a static IP and pings did not resolve the issue entirely, especially on the Windows host. Pinged the VMs every two minutes continuously plus pinged an external machine from (inside) the VMs every minute. The Windows Server host still lost networking repeatedly.

Interestingly, I got different results with different virtual NIC models. The Intel Pro 1000 MT desktop lost connectivity much earlier than the 1000 MT Server. It seems that we can use the ping workaround with the latter (for now) to maintain connectivity.